Apparatus for detecting and treating tumors using localized impedance measurement

Abstract

An apparatus for treating tumors comprises an elongated delivery device that includes a lumen and is maneuverable in tissue. An impedance sensor array is deployable from the elongated device and configured to be coupled to at least one of an energy source or a switching device. The impedance array includes a plurality of resilient members, at least one of the plurality being positionable in the elongated device in a compacted state and deployable with curvature into tissue from the elongated device in a deployed state. In the deployed state, the plurality of resilient members defines a sample volume. At least one of the resilient members includes an impedance sensor and at least a portion of the array is configured to sample tissue impedance through a plurality of conductive pathways. An energy delivery device is coupled to one of the array, the at least one resilient member or the elongated device.

1. An apparatus for impedance characterization and ablative treatment of tumors, comprising:
 an elongated delivery device including a lumen, the elongated delivery device being maneuverable in tissue; and 
 an impedance array comprising a plurality of resilient members being positionable in the elongated delivery device in a compacted state and deployable with curvature into tissue from the elongated delivery device in a deployed state and defining a sample volume in the deployed state, at least two of the plurality of resilient members being a sensor member and including a sensor for determining impedance, where each sensor member is operatively connected to a separate impedance energy source, at least some of said resilient members being electrodes which can be coupled to at least one ablating energy source for ablating tissue when electrical energy is supplied to the electrodes from the ablating source; 
 wherein said impedance array is effective to determine localized impedance. 
 
     
     
       2. The apparatus according to  claim 1 , wherein said impedance characterization is vector impedance characterization and at least a portion of the impedance array is configured to determine an impedance vector within a selectable tissue site. 
     
     
       3. The apparatus according to  claim 2 , wherein the impedance array is configured to detect real and imaginary components of the impedance vector or magnitude and phase angle of the impedance vector. 
     
     
       4. The apparatus according to  claim 1 , wherein said impedance characterization is multi-pathway impedance characterization and at least a portion of the impedance array is configured to sample tissue impedance through a plurality of conductive pathways. 
     
     
       5. The apparatus according to  claim 4 , wherein the plurality of conductive pathways are configured to be substantially evenly distributed or spaced within the sample volume. 
     
     
       6. The apparatus according to  claim 1 , wherein the plurality of resilient members includes a first, a second and a third resilient member. 
     
     
       7. The apparatus according to  claim 1 , wherein the sensor has a resistance gradient. 
     
     
       8. The apparatus according to  claim 7 , wherein the resistance gradient is along a length of the sensor and configured to compensate for resistive losses or hysteresis along the length of the sensor. 
     
     
       9. The apparatus according to  claim 1 , wherein at least a portion of the impedance arrays is configured to determine at least one of an intracellular impedance, an interstitial impedance or an intercellular capacitance. 
     
     
       10. The apparatus according to  claim 1 , wherein the impedance array is configured to determine a locus of impedance within the sample volume. 
     
     
       11. The apparatus according to  claim 1 , wherein the impedance array is configured to substantially simultaneously determine a first impedance profile at a first tissue site and a second impedance profile at a second tissue site. 
     
     
       12. The apparatus according to  claim 11 , where, when the impedance characterization is multi-pathway impedance characterization, the first pathway is positioned at a selectable angle relative to the second pathway. 
     
     
       13. The apparatus according to  claim 12 , wherein the first and second pathway have no common segments. 
     
     
       14. The apparatus according to  claim 12 , wherein the first and second pathway have a common origin. 
     
     
       15. The apparatus according to  claim 14 , wherein the first and second pathway have substantially the same pathway, the second pathway being in an opposite direction to the first pathway. 
     
     
       16. The apparatus according to  claim 1 , wherein the impedance array is configured to detect at least one of an indicator of cell necrosis, a tissue ablation volume, a cell necrosis volume, a tissue thermal volume or a tissue hyperthermic volume. 
     
     
       17. The apparatus according to  claim 1 , further comprising:
 logic resources coupled to at least one of the impedance array or the at least one ablating energy source, and 
 a processor operatively coupled to the logic resources. 
 
     
     
       18. The apparatus according to  claim 17 , wherein at least one of the impedance array or the logic resources is configured to determine or analyze tissue impedance or complex impedance at a frequency distinct from an ablation frequency. 
     
     
       19. The apparatus according to  claim 17 , wherein the logic resources are configured to identify a tissue condition or differentiate tissue responsive to an impedance signal from the impedance array. 
     
     
       20. The apparatus according to  claim 17 , wherein the logic resources are configured to analyze an impedance signal at a frequency having an increased tissue condition sensitivity relative to a frequency spectrum. 
     
     
       21. The apparatus according to  claim 20 , wherein the logic resources are configured to distinguish between normal and abnormal tissue, the abnormal tissue including at least one of abnormally mutated tissue, abnormally dividing tissue, cancerous tissue, metastatic tissue or hypoxic tissue. 
     
     
       22. The apparatus according to  claim 17 , wherein the logic resources are configured to distinguish between necrosed and non-necrosed tissue. 
     
     
       23. The apparatus according to  claim 17 , wherein the logic resources are configured to identify one of an inflection point, an asymptote, a minimum or a maximum of an impedance signal. 
     
     
       24. The apparatus according to  claim 23 , wherein the logic resources are configured to identify at least one of an endpoint, an amount of tissue injury or a tissue type utilizing at least one of the inflection point the asymptote, the minimum or the maximum of the impedance signal. 
     
     
       25. The apparatus according to  claim 17 , wherein the logic resources are configured to compare the impedance of the first tissue site to an impedance of the second tissue site. 
     
     
       26. The apparatus according to  claim 1 , wherein the logic resources are configured to identify an endpoint for an ablation procedure responsive to an impedance signal from the impedance array. 
     
     
       27. The apparatus according to  claim 1 , wherein the impedance signal includes at least one of an intracellular impedance, an interstitial impedance an intercellular capacitance or a complex impedance, and wherein the logic resources are configured to identify a tissue condition utilizing at least one of an impedance ratio including at least one of interstitial to intercellular impedance, real to imaginary impedance or impedance to capacitance. 
     
     
       28. The apparatus according to  claim 19 , wherein the impedance signal is a complex impedance and the logic resources are configured to identify a tissue condition of the sample volume utilizing real and imaginary components of the complex impedance signal. 
     
     
       29. The apparatus according to  claim 1 , further comprising:
 an advancement member coupled to the impedance array, the advancement member including an actuable portion, the advancement member configured to control deployment of at least a portion of the impedance array. 
 
     
     
       30. The apparatus according to  claim 1 , wherein at least a portion of the impedance array is configured to sample a complex tissue impedance through a plurality of conductive pathways and detect or measure an indicator of at least one of tumorous tissue or cell necrosis. 
     
     
       31. The apparatus according to  claim 1 , further comprising:
 a multiplexing device operatively coupled to at least some of said plurality of resilient members for multiplexing electrical energy between said plurality of resilient members. 
 
     
     
       32. The apparatus according to  claim 1 , wherein the at least one ablating energy source is selected from the group consisting of a RF source, a microwave source, and a laser source. 
     
     
       33. The apparatus according to  claim 32 , wherein said apparatus is switched between a bipolar mode and the mono-polar mode. 
     
     
       34. The apparatus according to  claim 1 , wherein said apparatus operates in a mono-polar mode, said apparatus further comprising:
 a ground electrode.